Purification of an antibacterial protein in the coelomic fluid of Nereis diversicolor (annelida, polychaeta). similitude with a cadmium-binding protein

Abstract

1. Coelomic fluid of Nereis diversicolor shows antibacterial activity 24 hr after inoculation with Escherichia coll, while fluid from untreated control does not. 2. This activity is detected by growth inhibition of E. coli or Micrococcus kristinae. 3. The thermolabile protein has been purified by two distinct methods using gel filtration and exchange ion chromatography. By SDS-PAGE, the molecular weight of this protein has been estimated at about 10 kDa. 4. The protein shows strong similitude with cadmium-binding protein (CBP) which is a dimer constituted by two 10 kDa subunits (Nejmeddine et al., 1988). 5. In Western Blot, monoclonal antibody against CBP reacted with the antibacterial protein. 6. Moreover, bacteriostatic activity of the coelomic fluid disappeared after incubation with polyclonal and monoclonal antibodies.